The present invention generally relates to power tools. More particularly, the present invention relates to power tools which utilize a fence for guiding work pieces during operation of the tool.
It has long been known that table saws as well as other saws and power tools have utilized fences for guiding work pieces during a cutting or similar operation. The fences are typically adjustable to accommodate variously dimensioned work pieces or to vary the amount of material that is being cut. Such fences are almost essential for cutting boards or sheet of material as they are being fed to the saw blade of table saw. Of course, fences are used for similar control with regard to many other kinds of power tools such as routers and shapers, miter saws, radial arm saws and the like.
Most table saws generally have a fence which is completely removable fence and which extends completely from the front to the back of the table top and include a clamping mechanism that is typically designed for the particular table saw so that it can be laterally adjusted to a desired position and clamped down. Also, most table saws have a runner, rail or other structure attached to the front of the table saw on which the fence can ride and when it is clamped down, the clamping end has a surface which will engage a complimentary surface of the rail so that an elongated fence portion is oriented in a direction that is perpendicular to the rail. However, many modern fences have the clamping end mechanism that is separately manufactured and is then attached to an elongated portion. Because they are separate pieces which are interconnected and can become misaligned, it is desirable to be able to calibrate the fence and adjust it so that the elongated portion is exactly perpendicular to clamping end mechanism, and the front rail. When the calibration is successfully completed, the elongated portion is also substantially parallel or true to the plane of the blade of the table saw.
If very close tolerances are desired in the cutting of work pieces, it is important for a user to be able to check to insure that the fence is accurately aligned. While it is possible to place lines or grooves in the table top to provide a reference of parallelism to the plane of the blade, uncertainty can remain as to whether the fence is true or not. An inexpensive system for determining and achieving true and accurate alignment is desirable.